[Cha Cha]

My Moka who is almost 3 yrs old, is suddenly itching and uncomfortable. The only thing different I have done recently was switch her food about a month ago from TOTW to Wellness small dog. The itching started 2 days ago. She has no apparent redness, or hives on her skin but she is visibly uncomfortable and not in any one particular spot-but all over. She does not have any fleas or signs of fleas, and the pads on her feet are not red or pinkish in color. Wednesday I did give her her sentinel heartworm but I do this monthly. My house is dry even though we are running a humidifier. Could she just have dry skin? Or, could it be her new food? She has itched enough under her jaw to just start irritating the skin, but when you pet her she just wants you to scratch her all over. Allergies have never been a problem for her but I know they can surface at any time. What can I try putting on her skin or giving her to give her some comfort? She is due for a routine wellness check, but until then???